Hypothesis
Snowshoe hares facing shorter snow seasons would compensate for coat-colour mismatch through plasticity, by shifting moult timing with snow conditions or changing hiding, fleeing and resting behaviour when mismatched.
What failed
Observing nearly 200 hares at two Montana sites over a wide range of snow conditions, moult timing differed between sites but was largely fixed within each site, with only minimal response to snow during the spring moult. Hiding, fleeing and resting-spot choices showed no evidence of responding to mismatch; season, site and vegetation cover mattered more.
Broken assumption
Seasonally camouflaged animals can buffer climate-driven mismatch through flexible moult timing or behaviour.
Why
The authors conclude that moult and behavioural plasticity in this species are too limited to offset mismatch, so adaptation would need natural selection.
From the published paper: Zímová et al. Proceedings of the Royal Society B Biological Sciences, 2014. ↗CC BY